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[4.14,146/267] crypto: ecdh - fix big endian bug in ECC library

Message ID 20191216174910.473333138@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

gregkh@linuxfoundation.org Dec. 16, 2019, 5:47 p.m. UTC 
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>


commit f398243e9fd6a3a059c1ea7b380c40628dbf0c61 upstream.

The elliptic curve arithmetic library used by the EC-DH KPP implementation
assumes big endian byte order, and unconditionally reverses the byte
and word order of multi-limb quantities. On big endian systems, the byte
reordering is not necessary, while the word ordering needs to be retained.

So replace the __swab64() invocation with a call to be64_to_cpu() which
should do the right thing for both little and big endian builds.

Fixes: 3c4b23901a0c ("crypto: ecdh - Add ECDH software support")
Cc: <stable@vger.kernel.org> # v4.9+
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


---
 crypto/ecc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
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Patch

--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -898,10 +898,11 @@  static void ecc_point_mult(struct ecc_po
 static inline void ecc_swap_digits(const u64 *in, u64 *out,
 				   unsigned int ndigits)
 {
+	const __be64 *src = (__force __be64 *)in;
 	int i;
 
 	for (i = 0; i < ndigits; i++)
-		out[i] = __swab64(in[ndigits - 1 - i]);
+		out[i] = be64_to_cpu(src[ndigits - 1 - i]);
 }
 
 static int __ecc_is_key_valid(const struct ecc_curve *curve,